cyl head indentations?

[7m-iata]

I've noticed on my BBK I see knicks or scratches in the combustion chamber, I've never noticed this with a stock cyl I've even ran my stock head on this cyl/piston and haven't seen them, but with the head included in my kit I do. Theres NO scratches in the cyl or on the piston and it doesn't affect the way it runs, just odd to me I've ran 3 different heads on this cyl so far and the one designed for the kit seems to be doing this... maybe low grade aluminum or something?